filters: Add test/server:filter_config_test (envoyproxy#14746)

As part of envoyproxy#14470, I'll be modifying the base filter interface to include an overridable dependencies() function. This is prep work.

Risk Level: Low (test only)
Doc Change: n/a
Release Notes: n/a
Signed-off-by: Auni Ahsan <[email protected]>

test/server/BUILD

@@ -100,6 +100,16 @@ envoy_cc_test(
     ],
 )
 
+envoy_cc_test(
+    name = "filter_config_test",
+    srcs = ["filter_config_test.cc"],
+    deps = [
+        "//include/envoy/server:filter_config_interface",
+        "//source/extensions/filters/http/common:pass_through_filter_lib",
+        "//test/mocks/server:server_mocks",
+    ],
+)
+
 envoy_cc_test(
     name = "hot_restart_impl_test",
     srcs = envoy_select_hot_restart(["hot_restart_impl_test.cc"]),

test/server/filter_config_test.cc

@@ -0,0 +1,42 @@
+#include "envoy/server/filter_config.h"
+
+#include "extensions/filters/http/common/pass_through_filter.h"
+
+#include "test/mocks/server/factory_context.h"
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+
+namespace Envoy {
+namespace {
+
+class TestHttpFilterConfigFactory : public Server::Configuration::NamedHttpFilterConfigFactory {
+public:
+  TestHttpFilterConfigFactory() = default;
+
+  Http::FilterFactoryCb
+  createFilterFactoryFromProto(const Protobuf::Message&, const std::string&,
+                               Server::Configuration::FactoryContext&) override {
+    return [](Http::FilterChainFactoryCallbacks& callbacks) -> void {
+      callbacks.addStreamDecoderFilter(std::make_shared<Http::PassThroughDecoderFilter>());
+    };
+  }
+
+  ProtobufTypes::MessagePtr createEmptyConfigProto() override { return nullptr; }
+  ProtobufTypes::MessagePtr createEmptyProtocolOptionsProto() override { return nullptr; }
+
+  std::string name() const override { return "envoy.test.http_filter"; }
+  std::string configType() override { return ""; };
+};
+
+TEST(NamedHttpFilterConfigFactoryTest, CreateFilterFactory) {
+  TestHttpFilterConfigFactory factory;
+  const std::string stats_prefix = "foo";
+  Server::Configuration::MockFactoryContext context;
+  ProtobufTypes::MessagePtr message{new Envoy::ProtobufWkt::Struct()};
+
+  factory.createFilterFactoryFromProto(*message, stats_prefix, context);
+}
+
+} // namespace
+} // namespace Envoy